Architecture, construction, transport

The basis of the work is the results of the historical and cultural research of inner-block buildings, including residential multistorey ones in Saint Petersburg. The author studied the history of the inner-block building at 23b Egorova Street, letter A, located in the projection of Ustinov house at 18 Izmailovsky Prospekt, that had been built as a revenue house and rented out in the early 20 century. The author also analyzed reconstructions, extensions, transformations of the building and its annexes in order to determine its historical and cultural significance and other valuable parameters. The analysis made it possible to establish the initial function of the building and to study its planning solutions typical for revenue houses of the period under consideration. According to the results, the building at 23b Egorova Street, letter A, has no memorial, historical, town-planning and architectural value, therefore, it cannot be classified as a historical building. Such studies are important both for the preservation of true cultural values and for changing the architectural appearance of the city for its future development.

Spatial development of ecological tourism territories is characterized by contradiction between recreational use and preservation of ecological and cultural heritage. Russian and foreign researchers devote their works to the objects of tourist territories. However, the principles of environmental education and behavioral norms are still poorly transferred through architecture. The authors propose representing the elements of the ecotourism territory arrangement as a unified information system in order to reduce the anthropogenic load. Each element of this system is subordinate, complements and is a continuation of the elements of higher ranks. This system addresses the main contradiction of ecotourism territories, and ecotourists move along the formed routes using norms and rules of environmental behavior. Visitor centers and ecological routes are identified as key elements of urban development of the ecotourism territory. They are characterized by ecological-educational, tourist-informational, cognitive-entertaining and research functions. The results of the study are important for systematization of knowledge in the field of ecotourism, as well as for the development of strategic territorial planning documents.

Strength and creep of frozen soils are among the main mechanical properties for time estimation in the design of construction objects. Based on experimental data, the authors determined deformational mechanical characteristics of frozen soil, including creep, and obtained a creep function of frozen soil. Using this creep function, the authors analytically determined the relaxation function of frozen soil using the broken lines method. This methodology can be used in the design of foundations for construction objects made of frozen soils.

Carrying out engineering geological surveys is a complex and responsible process. The reliability and safety of design solutions depend on the quality of their execution. This study assessed the quality of laboratory soil samples based on reports from engineering geological surveys conducted in Tyumen city and Tyumensky district. The assessment was based on 13 reports from 9 survey organizations. The Terzaghi and Lunne methods were used for evaluation. To achieve this, data from compression tests on soil samples, obtained from 505 reports, was processed accordingly. The data were presented as diagrams: for the sample as a whole; by organizations; by type and consistency of soil; by depth of sampling. The study concluded that the quality of the surveys was inadequate and identified factors contributing to this. The study provided recommendations for improving the quality of soil samples collected during engineering geological surveys.

 A crucial step in addressing the challenge of constructing shallow foundations on seasonally freezing heaving soils is performing temperature calculations of the soil foundation. The software packages Frost 3D and QFrost can be used for conducting these temperature calculations. This research compared the results of calculating frost penetration depths of a test site’s soil foundation using Frost 3D and QFrost with data from geotechnical monitoring. The test site was located in Tyumen, in the vicinity of the Bereznyaki settlement. The study found that using Frost 3D and QFrost software packages for modeling the soil foundation allows for determining frost penetration depths with an error of up to 3.5 %, indicating the reliability of the results and the possibility of using these software packages for performing temperature calculations.

Increased manganese concentration is characteristic not only of fresh water, but also of wastewater. Metal enters wastewater as a result of industrial activities such as manganese oxide ore beneficiation, galvanic cell production, and organic synthesis. Manganese compounds are strong poisons with pronounced cumulative effects. The effect leads to enzyme blockage, thyroid gland suppression, and accumulation in the liver and kidneys. Sorption method is used to remove manganese from natural water and industrial wastewater. This method can remove contaminants to any desired residual concentration. However, to mitigate the consequences of anthropogenic impact on the environment in the context of growing water consumption, the use of new, efficient materials is required. Currently, modified natural clay materials are being used for the purification of natural water and industrial wastewater. The authors investigated the extraction of manganese ions from aqueous solutions using modified diatomite. The diatomite was treated with a hydrochloric acid solution to increase the number of surface adsorption sites. Chemical modification of clay sorbents increases the pore space and specific surface area, which leads to an increase in sorption capacity. The experimental results showed an increase in the exchange capacity of the modified H-form: 1.45 mg/g compared to the native form – 0.63 mg/g. The values of maximum sorption capacity were 0.58 mg/g for the native form and 1.19 mg/g for the H-form. The optimal conditions for the sorption extraction of manganese ions were determined: 15.7 % for the native form and 63.2 % for the modified H-form.

A pressing issue for the railway industry is to enhance the stability and reduce the deformability of earth embankment structures constructed on weak foundations using the method of replacing weak soil. The authors determined the width of the weak soil at the base, requiring replacement, taking into account the requirements for deformability indicators that ensure the specified geometric parameters of the earth embankment under various soil foundation conditions. The numerical modeling was based on established theoretical principles in accordance with the sequence of construction stages for a high-speed railway line on weak foundations using the geotechnical software Plaxis 2D. By considering and evaluating different thicknesses of the weak soil layer to be replaced, the authors constructed a graph of the dependence of deformation on the principal stress at the point of plastic deformation development, and determined the value of the stable safety factor. The research made it possible to propose a numerical method for determining the slope stability coefficient. Analysis of current regulatory documents and calculation methods for earth structures on weak soils has confirmed the need to refine existing calculation methods.

The object of the study was fuel trim of the air-fuel mixture, in particular, short-term fuel trim by voltage change of the oxygen sensor installed before the catalytic converter during vehicle operation. Experimental studies were on the Bishkek – Osh (Kyrgyz Republic) highway at an altitude of 750–3200 m above sea level. It is characterized by flat, mountainous and high mountainous vehicle operating conditions. The experimental studies results were used to graph the dependence of short-term fuel trim on the change of oxygen sensor voltage during vehicle operation. The values of fuel trim parameters can be used to assess the state of the air-fuel mixture, as well as to make a conclusion about the technical condition of sensors, systems and mechanisms of the engine and elements of the car exhaust system. In addition, in normal operation of the engine, when the fluctuation of fuel correction indicators is ±10 %, fuel-economic and environmental indicators will be in fit. It should also be recognized that the modern automobile engines have a system of various sensors and electronic engine control unit, but they have their certain disadvantages in ensuring the stoichiometric composition of the air-fuel mixture (λ = 1).

The study examines the factors and causes of changes in the structural characteristics of road accidents on selected major streets of Tyumen from 2015 to 2022. The authors compared road accident data collected in 2015 and in 2022 for three main thoroughfare of the city: Respubliki street, 50 Let VLKSM – Zapolnaya – Chernyshevskogo street, Fedyuninskogo – Bypass Tyumen road – Zakaluzhskaya street. Structural characteristics of accident risks have been identified. The study found that the structure of accident risks for streets located in the city center, middle, and peripheral areas has undergone a significant change over the past 8 years. 1. On the central arterial Respubliki street, a decrease in the annual number of accidents by 19.1 % and a decrease in the annual number of injured in accidents by 20.0 % was observed. 2. On the section of 50 Let VLKSM – Zapolnaya – Chernyshevskogo – Polevaya street, there was an increase in the annual number of accidents by 34.5 % and an increase in the annual number of injured in accidents by 23.4 %. 3. On the section of Fedyuninskogo – Bypass Tyumen Road – Zakaluzhskaya Street, a 2-3-fold increase in road accident indicators was recorded: the annual number of accidents increased by 217.6 %, the annual number of injured in accidents by 136.7 %. In the city center, with an overall reduction in accident risks, the quantitative and qualitative ratios between accidents at intersections and on road segments have changed. The results of this study can serve as a basis for developing practical solutions to improve road safety.

Today, additive technologies are common used in different areas of human life and economics. However, the aspects of technological support for various parameters of accuracy in products obtained with 3D printing are not yet fully understood. This study investigates the problems of ensuring the required output products’ characteristics through a comprehensive approach, considering equipment, technological modes, and the work process itself. The study employed quality management methods, mathematical statistics, and frequency analysis as research tools. During experimental studies, batches of parts were printed. The parameters of the part accuracy were then measured and analyzed. The authors also examined the issue of printer elements’ resonant vibrations frequencies on the printing process output parameters. The study demonstrated that eliminating these frequencies by tuning equipment drives improves the accuracy of the resulting products. Further research will explore the impact of printing modes on the accuracy of products and the parameters of vibrational processes in printer elements. Obtaining this data will allow for more efficient technological preparation of the production of this class of products.